Pages in this set

Page 1

The Periodic Table
In the early 1800s, there were only 2 ways to categories elements- by their physical and
chemical properties and by their relative atomic mass.
An English chemist, John Newlands first arranged the elements in 1863. He noticed that if he
arranged the elements in order of mass,…

Page 2

Periodicity
In the Periodic Table there are trends in properties as you go down a group, but also many
properties vary in a fairly regular way as you move across a period from left to right.

The pattern is then repeated as you go across the next period.

The occurrence…

Page 3

Atomic Size

The size of an atom is determined by the space its electrons occupy.

Atoms become smaller as you move across a period, despite the increasing number of
electrons.

This is because the successive electrons adding on crossing a period enter the same electron
shell.